Re: [Qemu-devel] [Bug 1308542] Re: hang in qemu_gluster_init

[Bharata B Rao]

On Fri, Apr 18, 2014 at 02:38:57PM -0000, Soumya Koduri wrote:
> " glfs_init" cannot be called before since it checks for
> cmds_args->volfile_server which is allocated only in
> "glfs_set_volfile_server".   We should either modify "glfs_fini" or

Soumya - Thanks for offering to fix this in gluster.
(Ref: http://lists.gnu.org/archive/html/gluster-devel/2014-04/msg00192.html)

Kevin - I will wait for this fix to be available in libgfapi before
changing QEMU.

Regards,
Bharata.

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https://bugs.launchpad.net/bugs/1308542

Title:
  hang in qemu_gluster_init

Status in QEMU:
  New

Bug description:
  In qemu_gluster_init, if the call to either glfs_set_volfile_server or
  glfs_set_logging fails into the "out" case, glfs_fini is called
  without having first calling glfs_init.  This causes glfs_lock to spin
  forever on this bit:

        while (!fs->init)
                pthread_cond_wait (&fs->cond, &fs->mutex);

  And here's the bottom part of the backtrace when hung:

  #0  pthread_cond_wait@@GLIBC_2.3.2 () at 
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:183
  #1  0x00007feceebf58c3 in glfs_lock (fs=0x7fecf15660b0) at glfs-internal.h:156
  #2  glfs_active_subvol (fs=0x7fecf15660b0) at glfs-resolve.c:799
  #3  0x00007feceebeb5b4 in glfs_fini (fs=0x7fecf15660b0) at glfs.c:652
  #4  0x00007fecf0043c73 in qemu_gluster_init (gconf=<value optimized out>, 
filename=<value optimized out>) at 
/usr/src/debug/qemu-kvm-0.12.1.2/block/gluster.c:229

  I believe this can be fixed by simply moving the call to glfs_init
  after the call to glfs_new but before the calls to
  glfs_set_volfile_server or glfs_set_logging.

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